Electromechanical weft detector



May 2, 1950 H. A. WHITIN ELECTROMECHANICAL WEFT DETECTOR 2 Sheets-Sheet2 Filed Feb. 3, 1948 FIG.I6

INVENTOR HERBERT .4. WH/Tl/V ATTORNEY Patented May 2, 195

UNITED STATES PATENT OFFICE ELECTROMECHANICAL WEFT DETECTOR Herbert A.Whitiii, Worcester, Mass, assignor to Crompton & Knowles Loom Works,Worcester,- Mass., a corporation of Massachusetts Application February3, 1948, Serial No. 6,050

This invention relates to improvements in electromechanical weftdetectors for weft replenishing looms and it is the general object ofthe invention to provide a weft detector of this type more particularlyadaptable for use with very fine weft.

Weft detectors for fine artificial yarns must be sensitive andsufiiciently delicate in their operation to avoid yarn abrasion. In manyinstances this result is obtained by the use of electric weft detectorsrequiring a complement of bobbins provided with expensive metallicferrules. Sensitive side slipping weft detectors have also beendeveloped, but they have ordinarily given their indication mechanicallyin such a way as to require the exertion of sufiicient force to injuredelicate wefts.

It is an important object of the present invention to provide a weftdetector having a side slipping detector finger to permit use withnon-ferrule bobbins coupled with an electric circuit wherein the forcerequired for utilizing the indication of the weft detector isaccomplished electro-magnetically rather than by a force derived fromthe detector.

It is desirable to be able to adjust the tension of the weft detectorwith respect to the contact member of an electric switch associated withthe electric weft detector. The switch will ordinarily have a yieldablemember which is held in its normal position by a constant non-adjustablespring which must be overcome as the detector finger slips laterallywhen giving indication of weft exhaustion. The force of the switchspring may vary from switch to switch and it is desirable to compensatefor this variation so that thenet force exerted on the detector fingershall be the minimum required to return it to its detecting position. Toaccomplish this result it is a further object of the invention toprovide an adjustable spring opposed to the constant spring of theswitch so that it may be set to overcome the force of the switch springby a small amount just suflicient to move the detector finger back todetecting position after it has had a side slipping movement.

It is also desirable to be able to adjust the distance between the Weftdetector tip and its pivot and to accomplish this result it is a furtherobject of the invention to make the detector in the form of a wire orthe like slidable within a tube adjustably held on one arm of a detectorlever.

When the detector is made with the aforesaid wire and tube there islikelihood that the wire 9 Claims. (Cl. 139-273) will rotate withrespect to the tube and change the angular position of the detector tip.Since the latter must in all of its angular positions be capable ofeffecting some penetration of the weft on the bobbin it is a furtherobject of the invention to provide the detector tip with a set of pointsrather than the usual ridges so that the points when penetrating asufiicient supply of weft will prevent side slipping regardless of theangular position of the tip.

In order that the detector finger and its switch may be assembled as aunit for use in the types of weft replenishing looms in which thedetector is at the replenishing end of the loom, it is a further objectof the invention to mount the switch and detector finger on a slidemember normally held in rear detecting position but movable forwardly atthe time of bobbin transfer to clear the path of the incoming reservebobbin.

When a side slip weft detector is used at the replenishing end of a loomand is moved forwardly at transfer there is danger that a false orrepeated indication of exhaustion will be given resulting from swingingof the detector around its pivot. It is a still further object of theinvention to prevent closure of the detecting circuit when the detectoris moved forwardly on replenishing beats of the loom.

With these and other objects in View which will appear as thedescription proceeds, my invention resides in the combination andarrangement of parts hereinafter described and set forth.

In the accompanying drawings, wherein three forms of the invention areshown,

Fig. l is a plan View of the preferred form of the invention,

Figs. 2 and 3 are enlarged vertical sections on lines 22 and 3-3,respectively, of Fig. 1,

Fig. 4 is an enlarged rear view of the weft detector tip as viewed alongthe line ifl, Fig. 2,

Fig. 5 is a partial side elevation looking in the direction of arrow 5,Fig. 1,

Fig. 6 is an enlarged transverse section on line 66 of Fig. 5,

Fig. 7 is a detail view showing the interior of the electric switch usedwith the detector,

Fig. 8 is a detailed side elevation looking in the direction of arrow 8,Fig. 1,

Fig. 9 is a diagrammatic view showing the weft detector in detecting butnon-indicating position in full lines and in indicating position indotted lines,

Fig. 10 is a View similar to a portion of Fig. 1 showing a modified formof the invention,

Fig. 11 is a rear elevation on an enlarged scale looking in thedirection of arrow ll, Fig. 10,

Fig. 12 is a diagrammatic view showing the manner in which accidentalside slipping of the detector finger is prevented when moved forwardlyat the time of bobbin transfer,

Fig. 13 shows the electric circuit for the detector, 7

Fig. 14, similar to Fig. 1, shows the second modification,

Fig. 15 is an enlarged front elevation in the direction of arrow l5,Fig. 14,

Fig. 16 is a vertical section on line iii-l 5, Fig. 15, and

Fig. 1'? shows the electric circuit for the second form.

Referring more particularly to Fig. 1, a stationary supporting base 65generally made of cast iron is formed with a slot 56 in which extendsthe right end of a control lever I! of the type commonly used inmulticolor weft replenishing looms. The end of lever 17 shown in Fig. 1has a, downward movement of alternate beats'of the loom when the lay isat front center and the bobbin B being detected is at the weftreplenishing side of the 100m. Ordinarily this downward movement is freeand uninterrupted, but when a depleted supply of weft is being detecteda controller pin Or rod it normally out of the path of lever I1 is movedunder the latter to prevent the normal downward movement of its rightend. The other endof lever I! not shown is thereupon depressed to effectindication of weft exhaustion and initiation of a replenishing operationby means not shown but well understood.

Pin 18 is pivoted to the upper end of a small arm 15 secured to a shaft25 which is rockable in arms 2! and 22 extending forwardly from thesupporting base l5. Shaft 20 extends to the right as viewed in Fig. land has secured thereto a second short arm 23 differing somewhat fromthat ordinarily used when a mechanical weft detector is employedon-multicolor weft replenishing looms, but serving the same generalpurpose.

The weft detector which, generally designated at D, comprises astationary base 25 having a depending lug 26 by which the detector ismounted on the support l5. The base is formed asshown in Fig. 6 andguides a slide member 2'5. A compression spring 28 between the base 25and slide 21 urges the latter rearwardly and a stop screw 29 on theslide member 27 engages a stationary pin 35 on the base member 25 tolimit rearward movement of member 27. The latter is movable forwardlyagainst the action of the spring t the time of a weft replenishingoperation by means of a roll 32 carried by the transferrer mechanismdesignated generally at 33. This roll engages a lug 34 extendinglaterally from the member 2'! and moves the detector finger to bedescribed out of the path of the incoming bobbin. Extending rearwardlyfrom'slide member 2'! is an arm 35 formed with an upstanding stud 36held in angularly adjusted position on arm 35 by a lock nut 31, see Fig.3. The

upper enlarged end 38 of stud 36 has'collar 29 held in angularlyadjustable positionthereon by a set screw All. This collar'39 isprovidedwith downwardly extending slots 41 and is hollow as at 42 to receive atorsion spring 43 one end of which extends as at 44 through one of thescribed is of common construction and may be made as constructedheretofore.

In carrying the preferred form of my invention into effect I pivot adetector lever 55 on stud 35 and attach it to the other end 45 of spring:33. Spring 38 tends to turn lever 45 in a counter clockwise directionas viewed in Fig. l, but permits it to rock in a clockwise direction.Lever 55 has an arm 43 extending laterally from the stud 55 in adirection more or less parallel to the bobbin B being detected. Arm asis split as at 49 and a clamping screw 55 draws the upper and lowerparts 5i and 52 of the lever against a tube 53 to hold the latter inadjusted longitudinal position on the arm 58.

The tube supports a detector wire 55 slidable in a bearing 55 at therear of the tube and in a screw 51 threaded into the forward end of thetube. A light compression spring 58 surrounds that part of the wire 55within the tube and bears rearwardly against a shoulder 55 rigid withthe wire 55. By adjusting the screw 5'5 in and out of the tube the forceexerted rearwardly by spring 53 on the shoulder 65 can be varied.

The rear end of rod or wire 551s provided with a tip 52 which is rigidlyattached to the Wire, as by means'of a pin 63 shown in Fig. 2. This'tipmay be made of hardened fiber, a plastic, or metal, and its rear face isprovided with a number of points 65, see Fig. 4. These points aredistributed over the rear surface of the tip 5'2 and penetrate the weftbeing detected if sui1"1- cient weft for continued weaving is present.Points 55 replace the ridges customarily employed in those types of weftdetectors in which the tip does not rotate. In the present instance,however, wire 55 is free to turn relatively to its supporting tube 55and the several points will therefore always resist side movement of thetip if suflicient weft is present regardless of the-am gular position ofthe tip.

The detector lever 45 is provided with a second arm 68 extendingforwardly fromthe'stud Stand provided with an upright pin t9 whichengages an operating arm 15 of an electric iswitch designated generallyat S and shown more particularly in Fig. 7. This switch comprises a bodyof insulating material H which is secured to the top of slide member 21by means-of screws 72. Arm in has a pivotal connection 73 withrespecttothe base H and operates a small plunger l4 extending into base H toengage a leaf-spring i5 located in a chambe 15 within the base of theswitch S This-spring 75 normallytends to move the operating arm E0 totheleft as viewed in'Fig. 7 and therefore normally tries to rock' thedetector lever 45 in a-clockwise'direction as viewed in Fig. 1. Thistendency, however, is overpowered by the spring 43, and the" set screw5'8 permits an adjustment of the force exerted by the torsion spring 43.This force will ordinarily "be only slightly more than that required tooverpower the force of spring'i5 and the-latter will normally be in theposition shown in Fig. '7.

Switch S is provided with an electrode connected to a wire 3| and asecond electrode 82 which is flexible and connected to wire 83. Thislatter electrode is connected by a U-shaped clip 84 to the spring 15.The two electrodes 85 and 82 areinsulated from each other and when theparts'are in the normal non-contactingposition shown in Fig.7corresponding to non-indication of the weft detector electrode 82 willbe spaced When, however, the condition tip 62 along the bare bobbin,lever 45 will rock from the full line to the dotted line position ofFig. 9 and pin 69 will move to the left. This permits operating arm 18to move to the left, whereupon' plunger 14 also moves to the left andspring 15, being free to act, snaps electrode 82 to the right, Fig. '7,to engage electrode 88, thereby electrically connecting wires 8| and 83.

After the detecting operation is completed and the bobbin B movesrearwardly in the normal operation of the loom spring 43 will againoverpower spring 15 and the electrodes will return to the position shownin Fig. 7.

Electric connection of the wires 8I and 83 may be utilized to initiate aweft replenishing operation electro-magnetically in any on of severalways. As shown herein a solenoid 85 secured to a bracket 86 fastened toand projecting forwardly from the base I5 has a core 88 normally in downposition and connected to the previously mentioned small arm 23 securedto shaft 28. When the solenoid is energized as a result of closure ofswitch S the core is raised and rocks shaft 28 in such a direction as tomove th controller pin I8 rearwardly under lever I1. The solenoid isprovided with wires 98 and 9| which may be connected to any appropriateform of electric circuit controlled by the switch S and electricallypowered to energize the solenoid when the switch is closed, see Fig. 13.

While I have shown a particular form of solenoid and loom controllingpart I do not wish to be thus limited, since so far as certain featuresof my invention are concerned it will be suflicient if closure of switchS energizes any form of electromagnetic device which will initiate weftreplenishment. The tube 53, lever 45, and switch S are all supported byand move with the member 21 as a unit during forward movement of thedetector D by roll 32 during a weft replenishing operation. Core 88rests on shelf 89 of bracket 86 and by its weight returns pin I8 toforward position, after an indication of weft exhaustion is given.

Movement of slide 21 by roll 32 incident to a weft replenishingoperation may cause rocking of lever 45 about its axis with consequentfalse and undesired closure of switch S. To prevent this closure of theswitch I provide a guard 92 secured to the under side of base 25 as at93, see Fig. 6. This guard has a vertical preferably obliqu plate 94behind roll 32 but forward of arm 68 of lever 45 when slide member is inits normal rear position. Member 21 remains in rear position when thedetector indicates and plate 94 does not inter-. fere with arm 68. Whenthe slide is moved forwardly by roll 32, however, lever arm 68 isprevented from moving laterally and pin 69 prevents arm 18 from movingto the left. Switch S is therefore not closed and a false indication isavoided. Fig. 12 shows arm 88 in the forward position it assumes on areplenishing beat of the loom and also shows plate 94 in position toprevent substantial ocking of lever 45.

In the modified form of the invention shown in Figs. 10 and 11 thegreater part of the structure thus far described is utilized, but inplace of the lever 45 I employ a detector lever 95 having front and backlaterally extending arms 96 and 91 in which the detector wire 55 isslidably mounted. The tube is omitted, but the light compression spring58 tends normally to hold the detector 62 in rear detecting position. Inorder that tension of the spring 58 may b varied I provide an adjustingscrew 98 rotatable in the arms 96 and 91 with a head 99 notched as atI88 to receive a pin I8I securedin arm 91 to hold angular adjustjustedposition of the slide 21.

ments of screw 98. A clip I82 through which detector wire 55 passes hasa hub I83 screw threaded on screw 98 to move back and forth along thelatter as it is turned. The compression of spring 58 can therefore ,bevaried to adjust the rearward force exerted by tip 62 against the weftbeing detected.

As already stated it is necessary to prevent closure of the detectorcircuit at the time of re plenishment. In the invention this isaccomplished by mechanical engagement of guard or stop 92 with lever 45as the latter tends to swing on its pivot incident to the forward andbackward reciprocation of slide 21. In the second modification of theinvention lever 45 is permitted to swing with resultant closure ofswitch S, but electrical means prevent closure of the detecto circuit atweft replenishment.

The adjusting screw 29 is provided at its front end with a head I85 bymeans of which the back and forth position of the slide 21 may beadjusted. The rear end of screw 29 engages the stationary stud 38, hencethe head I85 is always in the same position regardless of the back andforth ad- A leaf spring I86 is mounted on the base 25 but insulatedtherefrom by means of a block of insulation I81 and screws I88 whichhave insulating bushings I89, as shown in Fig. 16. The switch I86 isstationary and when the detector slide 21 is in its normal rearwardposition engages head I 85, which serves as a grounded contact.

Under normal detecting conditions for this second modification thecircuit as shown in Fig. 17 will normally be open due to the fact thatswitch S is open, but the contacts I85 and I86 will be closed. When thelever 45 swings to indicate weft exhaustion the slide support 21 remainsin rear position as already described for the preferred form of theinvention and the circuit will be closed through the switch S, contactsI85 and I86, the transformer T and the solenoid 85 to initiate a weftreplenishing operation of the loom. When the latter occurs roll 32 willmove forwardly against lug 34 and the slide 21 will advance, but indoing so the contact head I05 will move forwardly to the dotted lineposition shown in Fig. 17 and be out of engagement with the springcontact I86. Should detector lever 45 swing under these conditions andclose switch S there will be no closure of the detector circuit and afalse indication will be avoided.

From the foregoing it will be seen that I have provided a simple form ofelectro-mechanical weft detector wherein the detector lever 45 is actedupon by a relatively strong adjustable spring which overpowers a weakerspring 15 within the switch S. Springs 58 and 15 are collectivelystronger than spring 43, and spring 58 has; a strengthgreater than thedifference in the: strengths of springs 43 and 15. It will also be, seenthat the normally open switch S and detector arm 45 are both mounted onthe slide sup-- port or member 21 to form a unit movable forwardly onstand or base 25 by roll 32. Also, the tube 53 is adjustablelongitudinally in arm 48 along an axis at one side of stud 36 by reasonof the clamp screw 58 of lever 45, thereby permitting an adjustment inthe distance between stud 38 and the detector tip 62. This adjustmentalso permits a variation in the angle of the line joining the stud 36and tip 82 relatively to the surface being detected. The tip 62 isprovided with a rear surface comprising a series of weft penetratingpoints which effectively prevent side slipadjusting screw on the memberengaging the stop to adjust the rearward position of the member on thestand, the member being normally in a rearward position on the stand butmovable thereon to a forward position on weft replenishing beats of theloom, an electric switch closed upon indication of weft exhaustion whenthe member is in rear position, a contact normally electrically engagingthe adjusting screw when the member is in rearward position butincapable of engaging the screw when the member is in forward position,and loom controlling electric circuit means having the switch, contactand screw in series and capable of closure when the member is in rearposition but incapable of closure when the member is in forwardposition, said screw and contact engaging each other for all adjustedpositions of the member relatively to the stand when the screw engagessaid stop.

HERBERT A. WHI'I'IIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

Payne Mar. 3, 1936

